Three-Dimensional Rayleigh-Benard Convection of a Rarefied Gas: DSMC and Navier-Stokes Calculations
BULGARIAN ACADEMY OF SCIENCES SOFIA INST OF MECHANICS
Pagination or Media Count:
The three-dimensional Rayleigh-Benard convection of a rarefied gas is studied numerically by using DSMC and Navier-Stokes finite difference methods. We present the results obtained in a three-dimensional box with an aspect ratio ALxLyLz at a fixed wall temperature ratio rTcTh0.1. In general, the three-dimensional results confirm the validity of the zone of convection obtained in the previous authors two-dimensional considerations. A detailed analysis has been performed for Knudsen number Kn0.02 and A221, A331, and A 441 and different Froude numbers ranged within the zone of convection. As result, a variety of different stable convection patterns in form of rolls and squares has been obtained. For the lowest Knudsen numbers computed, Kn0.001 and Kn0.002 , Froude number Fr 1.0, and a fixed aspect ratio A221, an irregular chaotic flow in form of unstable polygonal patterns has been observed.
- Numerical Mathematics
- Fluid Mechanics
- Statistics and Probability